Hexamethylene diisocyanate
Structural formula | ||||||||||||||||
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General | ||||||||||||||||
Surname | Hexamethylene diisocyanate | |||||||||||||||
other names |
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Molecular formula | C 8 H 12 N 2 O 2 | |||||||||||||||
Brief description |
colorless to yellowish liquid with a pungent, unpleasant odor |
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External identifiers / databases | ||||||||||||||||
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properties | ||||||||||||||||
Molar mass | 168.20 g mol −1 | |||||||||||||||
Physical state |
liquid |
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density |
1.05 g cm −3 |
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Melting point |
−67 ° C |
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boiling point |
255 ° C (decomposition) |
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Vapor pressure |
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solubility |
Decomposes in water |
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Refractive index |
1.4585 (20 ° C) |
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safety instructions | ||||||||||||||||
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MAK |
0.005 ml m −3 or 0.035 mg m −3 |
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Toxicological data | ||||||||||||||||
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C |
Hexamethylene diisocyanate (or more precisely 1,6-hexamethylene diisocyanate , systematically 1,6-diisocyanatohexane ) is a chemical compound from the group of aliphatic isocyanates . It is a colorless to yellowish, toxic liquid with a pungent odor.
Extraction and presentation
Hexamethylene diisocyanate can be obtained by reacting hexamethylene diamine with phosgene and then purifying it.
properties
Physical Properties
Hexamethylene diisocyanate vapors are six times as heavy as air.
Chemical properties
The compound can react violently to explosively with alcohols in the presence of bases if the dilution is insufficient.
Safety-related parameters
Hexamethylene diisocyanate forms flammable vapor-air mixtures at high temperatures. It has a flash point of 130 ° C. The explosion range is between 0.9% by volume (64 g / m 3 ) as the lower explosion limit (LEL) and 9.5% by volume (676 g / m 3 ) as the upper explosion limit (UEL). The ignition temperature is 400 ° C. The substance therefore falls into temperature class T2.
use
Hexamethylene diisocyanate is an essential raw material for polyurethane - lacquers . Almost the entire amount consumed in Germany is used for paint precursors for the automotive and furniture industries, such as B. HDI biuret , HDI isocyanurate and HDI uretdione are further processed.
safety instructions
If heated to a high temperature ( flash point 130 ° C), hexamethylene diisocyanate vapors can form an explosive mixture with air.
Monomeric isocyanates always have a certain vapor pressure , which means that reactive substances are in the gas phase. In addition to reactivity, there is also the possibility of inhaling isocyanates. To avoid this additional risk, isocyanates are oligomerized. Oligomerization here means the enlargement of the molecules. Larger molecules always have lower vapor pressures and thus reduce toxicity . Possible ways of oligomerization are, for. B. the reaction of 3 mol HDI with trimethylolpropane or the reaction of 3 mol HDI to form an HDI isocyanurate as mentioned above.
See also
Individual evidence
- ↑ a b c d e f g h i j k l m n Entry on hexamethylene 1,6-diisocyanate in the GESTIS substance database of the IFA , accessed on May 29, 2019(JavaScript required) .
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-280.
- ↑ Entry on Hexamethylene diisocyanate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
- ↑ OECD : Screening Information Dataset (SIDS) Initial Assessment Report (SIAR) for Hexamethylene diisocyanate , accessed on November 4, 2014.
- ↑ PG Urben; MJ Pitt: Bretherick's Handbook of Reactive Chemical Hazards . 8th edition, Vol. 1, Butterworth / Heinemann 2017, ISBN 978-0-08-100971-0 , p. 596.
- ^ A b c E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
- ^ Report on diisocyanates at the BGFA
- ↑ Ulrich Poth: Synthetic binders for coating systems . Vincentz Network, Hannover 2016, ISBN 978-3-86630-611-0 .